BMW is celebrating the 30th anniversary of the original e28 M5. BMW Motorsports started developing the mighty sedan in 1984 and presented it to the public at the 1985 edition of the Amsterdam Motor Show.
The idea of a 5-Series-based sports sedan wasn’t new – BMW M built a performance-focused version of the E12 5 called M535i in 1980 and 1981. The M535i was powered by a 218-horsepower 3.5-liter straight-six engine and it featured a host of chassis and suspension tweaks that noticeably improved handling. Production was limited because the M535i was essentially the textbook definition of a niche product, but it was well-received and the same treatment was later applied to the e28 5-Series (pictured in the gallery below).
M engineers believed they could build an even more potent version of the e28 by simply rummaging through the BMW parts bin. The centerpiece of the project was the 3.5-liter straight-six M88 engine that debuted in the M1 sports car in 1978. A tuned version of the mill had already been shoehorned in the M635 CSi (e24) that was presented at the 1983 Frankfurt motor Show, creating a fantastic driving machine that received rave reviews from European journalists. Skeptics said installing the 3.5-liter under the hood of the e28 was a wild idea, but no one could deny that it was a relatively easy thing to do from a technical point of view because the 6 and the 5 rode on the same platform.
For use in the original M5, the M1’s 3.5-liter was tuned to produce 236 horsepower at 6,500 rpms and 251 lb-ft. of torque at 4,500 rpms, figures that made the M5 considerably more powerful than the M535i. Linked to a five-speed manual transmission that spun the rear wheels, the M5 sprinted from zero to 62 mph (100 km/h) in 6.5 seconds and reached a top speed of 152 mph (245 km/h).
The extra power was kept in check by a M-designed sport suspension, a limited-slip differential and larger disc brakes on all four corners.
The M5 eschewed the M535i’s aerodynamic body add-ons in favor of a more discreet, wolf-in-sheep’s-clothing look. As a result, it stood out from the regular e28 thanks to large alloy wheels mounted on Michelin TRX tires, a slightly lower ride height, a small lip spoiler up front and “M5” emblems affixed to the radiator grille and the trunk lid.
Inside, the M5 was essentially identical to a regular e28 but it was fitted with a M-specific three-spoke steering wheel, sport seats for the front passengers and a host of unique bits and pieces including the instrument cluster and the shift knob. The M5 stayed true to its luxury sedan roots and it could be ordered with a host of premium features including leather upholstery, a glass sunroof, air conditioning, heated seats and sunshades for the rear passengers.
Like the M535i, the M5 was a niche model that was largely hand-built by BMW M so its price tag was high and production was initially low.
BMW caved in to popular demand and introduced a U.S.-spec version of the M5 in 1986. It was powered by an evolution of the Euro-spec car’s 3.5-liter that was fitted with a catalytic converter in order to comply with the stricter emissions regulations that were enforced by the EPA. Power dropped to 252 horsepower and 243 lb-ft. of torque, though BMW promised that performance remained roughly the same.
U.S.-spec cars featured a wide array of EPA-mandated bits and pieces like 5-mph bumpers, side marker lights and sealed beam headlights, and they were equipped with 16-inch alloy wheels, a deeper front air dam and a small spoiler bolted to the trunk lid. U.S.-spec cars were also much better equipped than their Euro-spec counterparts.
The M5 retailed for $46,500 in 1988, the only model year it was offered in the United States. That same year, the 7-Series lineup started at $53,000, the M6 retailed for $55,960, the Mercedes-Benz 300TE (w124) sold for $46,980 and the V12-powered Jaguar XJ-S stickered for $41,500.
E28 M5 production ended in late 1987 after a little over 2,200 examples were built. The original M5 was replaced by a brand new, 315-horsepower model based on the e34 5-Series in August of 1988.
All photos courtesy of BMW’s archives department.